park lights flash with turn signal

Discussion in 'Lighting & Illumination' started by extrabigjon, Dec 24, 2015.

  1. extrabigjon

    extrabigjon GMFS Member

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    When my headlights are off the park lights and license plate lights flash when a turn signal is activated. With the headlights on all the lights function normally. For example, with the headlights off and left turn signal activated. The left turn signal blinks like it should AND the license plate light and right rear park lights blink also the right front 194 led will flicker very faint.

    My previous known good configuration was led's from vled everywhere inside and out except the third break, cargo and 3157's in the tails. I then installed led's in the third break light and four 3157's in the tails, also clipped the 7 pin on the stock flasher to prevent hyper flash.

    To trouble shoot I installed a new LM487 flasher that is comparable with led's, no change
    Put the stock 3157 bulbs back in the tails and unplugged the third break light, no change
    Unplugged all four connections from the distribution block by the spare tire and the factory trailer plug from the bumper at the same time, the front opposite 194 led of the selected turn signal will flash at normal brightness instead of a flicker.

    Took it to the dealer and they couldn't fix it. They said they cleaned some grounds and there guess is the taillight harness in the rear. How could a new taillight harness fix it if the problem still persists when the harness is unplugged?

    Can't really throw parts at this and hope for the best.
     
  2. Jake_Chevy

    Jake_Chevy GMFS Member

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    Id say you have a short in the harness somewhere. Best of luck to you.
     
  3. extrabigjon

    extrabigjon GMFS Member

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    Took apart the fusebox under the hood. Looks good and no signs of mice.
     
  4. Jake_Chevy

    Jake_Chevy GMFS Member

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    did you say you cut the 7 pin??? I run all LEDS in my truck... No issues and I did nothing with my 7 pin.
     
  5. extrabigjon

    extrabigjon GMFS Member

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    A quick how to on clipping the 7 pin on the stock flasher and no messing with load resistors. The lights will flash slightly faster then stock, about 1.5-2X faster than stock. Nowhere near a hyperflash or strobe speed.

    I tried a LM487 flasher made for led's thinking I damaged something while clipping the 7 pin. It did not fix my issue, it was louder and more annoying also, so I returned it and now I'm using the modified stock one.
     
  6. Kellen_E

    Kellen_E GMFS Member

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    You have voltage feed back from your turn signal to your parking lamps it sounds like. Do you kno if the switch for your blinker is in series on the ground side or is it on the positive side? What year and model vehicle is it?
     
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  7. extrabigjon

    extrabigjon GMFS Member

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    Truck is a 2004 silverado. Don't know how the turn signal switch is wired. I checked the tow plug in the bumper with a testlight. The park lamps flash with the turn signal also.
     
  8. Kellen_E

    Kellen_E GMFS Member

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    Is the tow plug stock or aftermarket?
     
  9. extrabigjon

    extrabigjon GMFS Member

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    Factory tow package with Hopkins 30955 plug, don't like to mess with adapters. Connections are shinny with dielectric grease.
     
    Last edited: Jan 1, 2016
  10. Kellen_E

    Kellen_E GMFS Member

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    Look at the wires at each turn signal where they go into the plug for the lights, there could be a short between the wire for the turn signal and parking lamp
     
  11. extrabigjon

    extrabigjon GMFS Member

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    I don't think it is in the rear taillight harness. The connections on the grey distribution block by the spare tire are:
    blue=incoming power
    grey=left taillight
    black=right taillight
    brown=license plate

    With all four of these unplugged at the same time. It would make the front corner 194 led, on the opposite side of the selected turn signal flash at normal intensity instead of a faint flicker. Example, with the right turn signal activated the left front corner 194 led flashes at normal intensity.

    Remember, with my issue it doesn't matter what turn signal I use. Either one will make the park lights and license plate lights flash. I think it has to be somewhere the left, right, and park lights share a connection or I have a pile of wires smashed. That is why I guessed at the flasher module.
     
  12. Kellen_E

    Kellen_E GMFS Member

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    Do you have a connection under the hood like the obs trucks have to disconnect all the lights in front?
     
  13. extrabigjon

    extrabigjon GMFS Member

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    I don't know.
     
  14. Kellen_E

    Kellen_E GMFS Member

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    I would look and if you do disconnect it and if the problem is still there at least it will narrow down the location.
     
  15. extrabigjon

    extrabigjon GMFS Member

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    Plugged in a trailer with a 4 flat and led lights. With the headlights off, using the turn signals the truck acts fine but some of the running lights on the trailer flash. With the hazards on, the license plate lights on the truck flash and a few more running lights on the trailer flash.
     
  16. extrabigjon

    extrabigjon GMFS Member

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    If I remove one of the front v3 amber turn signals, doesn't matter what side, and replace it with a 3457 incandescent bulb. The turn signals appear to function normally. Until I turn on the hazards then the license plate lights flash. If I put 3457 incandescent bulbs in both front turn signals. The hazards and turn signals appear to function normally.

    No dual turn signal mod or switchbacks just clipping the 7 pin. The v3 amber tritons in the front are the version 2.
     
  17. wade_660

    wade_660 GMFS Member

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    Dumb question but the polarity is right on all the LEDs right? I don't know much about the flashers but that would also be a focal point for me to check.


    Sent from my iPhone using Tapatalk
     
  18. extrabigjon

    extrabigjon GMFS Member

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    The 3157 led's will only work one way. The 194's are dual polarity. Meaning they can be installed in the socket either way and work.

    I put my 3157 amber led's in another 2004 Silverado that is bone stock and waited till dark to check them. With both front 3157 led's in the donor truck and the hazards on, both license plate lights barely flicker. Have to about put your face right over the license plate light to see it. The donor truck does not act up with only one led or with the turn signals. It must be both 3157 led's and the hazards on. I talked to vled with my findings and they are sending me new drivers for those two bulbs. Hopefully this will fix my problems.
     
  19. extrabigjon

    extrabigjon GMFS Member

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    I installed the new drivers today without resistors, they are not needed because of clipping the 7 pin, and that did not fix it. Then I unplugged every light on the front end at the same time. This would be the high, low, front turn, DRL and corner lights. The rear park lights and license plate lights still flashed with the turn signals when the headlights are off.

    Put everything back together with the new drivers. A new problem showed up when I turned my park lights on. Some of the led's in both mirrors are lit up halfway and both dash turn signal indicators are dimly lit. When I use a turn signal it only clicks once. Hazards only click once also.

    To get the mirror lights and dash indicators off I put the old drivers back. The old drivers are version 2 with a removable fuse to disable the builtin resistors. When I remove the fuse, disabling the resistors, the mirror signal lights and dash indicators are dimly lit and the turn signal clicks only once. Put the fuse back in to enable the resistors and they go out and the turn signal blinks as it should.
     
  20. extrabigjon

    extrabigjon GMFS Member

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    Here is a video showing my issue. No sound on this.
    [​IMG]
     

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